Field of the Invention
This invention relates to a device for mounting a terminal to an electric indicator, and more particularly to a terminal mounting device having a construction which can prevent the occurrence of a displacement and deformation in a gauge support plate of the indicator when the terminal is mounted to the indicator with a screw, thereby preventing the occurrence of an indication error in the indicator.
Description of the Prior Art
Conventionally, a terminal is mounted to an electric indicator in the manner illustrated in FIGS. 1 to 3.
The figures show a fuel gauge for a motor vehicle. The fuel gauge includes a gauge support plate 1 made from an electrically insulating material. On the gauge support plate 1, there is provided a bottom bearing 2. In addition, on both sides of the bottom bearing 2, two dial support poles 3 are located, between which is spanned a support plate 4. The lower end of a pointer shaft 5 is axially supported on the bearing 2, and the upper end of the pointer shaft 5 is axially rotatably supported by being inserted through a small hole 4a which is formed in the support plate 4.
The upper end of the pointer shaft 5 is inserted under pressure into a pointer 6, and a lever 7 with a slit 8 formed on it is fixed at the midpoint of the pointer shaft 5. An U-shaped bimetal 12 is formed by a temperature compensating section 9 and a movable leg 11 with a heating wire 10 wound around it. One end of the temperature compensating section 9 is fixed to an adjusting plate 13 which is attached to the gauge support plate 1. Further, a pin 14 is attached by welding to the tip of the movable leg 11 on which the heating wire 10 is wound, and the pin 14 is slidably engaged with the slit 8 in the lever 7. The lever 7 is turned by the bending of the movable leg 11 of the bimetal 12 in response to the amount of heat generated by the heating wire 10, and the pointer 6 is arranged to indicate the scales on a dial 15 which is fixed on the dial support sections 3.
In the fuel gauge, on the edge of the gauge support plate 1 made of an electrically insulating material, there are formed two cavities 19 to which a terminal 16 is attached, respectively. One of each of the ends of the heating wire 10 of the bimetal 12 is connected to one of the terminals 16, respectively.
As shown in FIG. 3, the terminal 16 includes an inserting section 16a and a wire connecting section 16b. A pair of engaging projections 17 are provided on both sides of the inserting section 16a of the terminal 16, respectively. In addition, at the center of the inserting section 16a, there is formed a screw fitting section 18. protruded from the inner peripheral wall of the cavity 19, there are formed engaging sections 20 for preventing the dropping of the terminal 16 through engagement with the projections 17 of the terminal 16. Also, on the bottom surface of the cavity 19 of the gauge support plate 1, there is formed a through hole 21 which corresponds to the screw fitting section 18 of the terminal 16. Under the gauge support plate 1, a meter body 22 which encloses the electrical indicator is provided. The meter body 22 has two through holes 23 which also correspond to the locations of the screw fitting sections 18, respectively. As illustrated in FIG. 2, under the meter body 22, there is provided a wiring board 25 connected to an electrical source (not shown), which also has two through holes 25a corresponding to the locations of the screw fitting sections 18, respectively. A screw 24 which is inserted via a washer 26 and the through holes 21, 23 and 25a beneath the wiring board 25, is engaged with the screw fitting section 18 of the terminal 16 to allow the connection between the terminal 16 and the gauge support plate 1, whereby an electrical circuit between the electrical source and the terminals 16 is completed.
However, in mounting the terminal 16 to the indicator in the above-described fashion with the screw 24, there sometimes occurred errors in the gauge indication of the electric indicator. The errors are caused by a displacement and deformation in the gauge support plate 1, the meter body 22 and the wiring board due to a tightening force of the screw 24. For example, such errors may result from deviations in the positioning between the through hole 21 of the gauge support plate 1, the through hole 23 of the meter body 22, or the through hole 25a in the wiring board 25 and the screw fitting section 18 of the terminal 16, or from a gap between the gauge support plate 1 and the meter body 22.
In addition, errors may be generated in the gauge indication of the indicator which are caused by the deformation due to twisting, along with the terminal, of the gauge support plate 1 caused by a tightening force of the screw 24, since little clearance is provided between the terminal and the inner surface of the cavity 19.